US 12,255,630 B2
Transversely-excited film bulk acoustic resonator with oxide strip acoustic confinement structures
Andrew Kay, Provo, UT (US); Sean McHugh, Santa Barbara, CA (US); John Koulakis, Los Angeles, CA (US); and Albert Cardona, Santa Barbara, CA (US)
Assigned to Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Apr. 12, 2022, as Appl. No. 17/719,311.
Application 17/719,311 is a continuation in part of application No. 17/555,353, filed on Dec. 17, 2021.
Application 17/555,353 is a continuation in part of application No. 17/542,290, filed on Dec. 3, 2021.
Claims priority of provisional application 63/237,050, filed on Aug. 25, 2021.
Claims priority of provisional application 63/208,503, filed on Jun. 9, 2021.
Claims priority of provisional application 63/191,897, filed on May 21, 2021.
Claims priority of provisional application 63/187,932, filed on May 12, 2021.
Claims priority of provisional application 63/182,465, filed on Apr. 30, 2021.
Prior Publication US 2022/0360251 A1, Nov. 10, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H03H 9/56 (2006.01); H03H 3/02 (2006.01); H03H 9/02 (2006.01); H03H 9/205 (2006.01)
CPC H03H 9/568 (2013.01) [H03H 3/02 (2013.01); H03H 9/02157 (2013.01); H03H 9/02228 (2013.01); H03H 9/205 (2013.01)] 19 Claims
OG exemplary drawing
 
7. A filter comprising:
a substrate;
a piezoelectric layer supported by the substrate;
three or more diaphragms, each diaphragm comprising a respective portion of the piezoelectric layer that is over a cavity; and
a conductor pattern on a front surface of the piezoelectric layer, the conductor pattern comprising interdigital transducers (IDTs) of three or more acoustic resonators, each IDT comprising first and second sets of interleaved fingers extending from first and second busbars respectively,
wherein;
the interleaved fingers extend onto a respective diaphragm of the three or more diaphragms, and
overlapping portions of the interleaved fingers define an aperture of the respective acoustic resonator;
wherein at least one of the three or more acoustic resonators further comprises:
a first dielectric strip on the front surface of the piezoelectric layer, a first portion of the first dielectric strip under the IDT fingers in a first margin of the aperture and a second portion of the first dielectric strip extending into a first gap between the first margin and the first busbar; and
a second dielectric strip on the front surface of the piezoelectric layer, a first portion of the second dielectric strip under the IDT fingers in a second margin of the aperture and a second portion of the second dielectric strip extending into a second gap between the second margin and the second busbar.